Roy Halladay is leaving major-league baseball the way he entered it – as a member of the Toronto Blue Jays.

The two-time Cy Young Award winner re-signed Monday with the team that drafted and developed him into one of the generation’s best pitchers, and then he immediately announced his retirement.

Admired and respected across the game for his durability, work ethic and fierce determination, Halladay fought through shoulder problems last season and faced just three batters in his last outing, a 4-0 Philadelphia Phillies loss to the Miami Marlins that represented the shortest start of his career.

After that game, when he couldn’t top 83 m.p.h., Halladay phoned the surgeon that removed bone spurs and repaired the frayed labrum in his right shoulder back in May and was prescribed rest, nothing more.

Still, at 36 and with 2,749.1 big-league innings on the odometer, the chances for a recovery didn’t look good, especially when Halladay also revealed that he had been fighting a genetic diet-related illness.

Monday’s retirement was an acknowledgment that his body had no more to give the game.

That he chose to hang up his No. 32 as a member of the Blue Jays is an appropriate end for one of the organization’s best home-grown players.

His departure after the 2009 season remains a painful moment for the franchise, a split driven by Halladay because of then GM J.P. Ricciardi’s inability to build a winner around him.

Halladay twice signed below-market extensions with the Blue Jays leading into that fateful 2009 season, when he was publicly shopped by Ricciardi prior to the trade deadline and was eventually dealt by Alex Anthopoulos during the off-season.

The Blue Jays got Kyle Drabek, Travis d’Arnaud (who helped land R.A. Dickey) and Michael Taylor (who became Brett Wallace, who became Anthony Gose) in return, while Halladay earned a second Cy Young Award and two trips to the playoffs, neither of which produced the championship he so dearly coveted.

His first post-season appearance did lead to one of the signature moments of his career – a no-hitter against the Cincinnati Reds in the 2010 NLDS, a feat all the more impressive given that he’d already thrown a perfect game against the Marlins on May 29 of that year.

A first-round pick, 17th overall, in the 1995 draft, Halladay flashed his brilliance in his second career big-league outing, a 2-1 win over the Detroit Tigers on Sept. 27, 1998, when he lost a no-hitter with two out in the ninth inning on a Bobby Higginson home run.

His ascension to stardom was derailed by struggles so severe in 2000 and early 2001 that the Blue Jays sent him all the way down to single-A, where pitching guru Mel Queen rebuilt his delivery and mental approach to the game.

Halladay returned midway through the 2001 season and never looked back, throwing at least 220 innings in eight of the next 10 seasons (forearm problems cut his season short in 2004 while a fractured leg ruined a brilliant 2005).